576 PHYSICS, PROGRESS OF, IN 1900. 



PHYSIOLOGY. 



concludes that the motion of an electrified body 

 does not appear to produce any magnetic effect 

 in its vicinity. 



Magnetism. Theory. Lang (Annalen der 

 Physik, July) interprets the so-called " ampe- 

 rian " molecular currents as convection currents 

 produced by the revolution of negative electrons 

 as satellites around the heavier positive electrons. 

 The usual velocity is that of light, and if it be- 

 comes larger the satellites may change the elec- 

 tron around which they revolve. 



Magnetization. Maurain (Comptes Rendus, 

 Aug. 13) finds that on electrolyzing a solution of 

 ferrous sulphate in sodium pyrophosphate inside 

 a magnetizing spiral adherent brilliant magnet- 

 ized deposits of iron are obtained, the intensity 

 of whose magnetization is constant for the dif- 

 ferent layers of the deposit, but is greater as the 

 field in which it is obtained is stronger. The 

 coercive force is enormous, and the reversal of 

 the magnetization may be effected suddenly for 

 a very small variation in the field. 



Hysteresis. Sheldon (Electrical World and 

 Engineer, Feb. 10), to test the supposition that the 

 retentivity and coercivity of magnetic substances 

 (the two factors of hysteretic quality) might be 

 dependent on the distance between their mole- 

 cules, experimented with different arrangements 

 of compass needles. When these were placed in 

 line the magnetizing force required to break up 

 the arrangement decreased as the distance be- 

 tween the pivots of the needles increased. The 

 decrease does not become zero, however, but ap- 

 proaches a constant value. When the needles are 

 arranged in multiple rows the polarity is more 

 easily reversed owing to the influence of the rows 

 on each other. As the distance between the rows 

 is increased, the critical magnetizing force is in- 

 creased, because the demagnetizing influence of 

 the rows on each other is decreased. 



Loss of Electric Charge. Phillips (Royal Soci- 

 ety Proceedings, 65, 1899) finds that under certain 

 conditions an electrified body loses its charge in the 

 neighborhood of a magnetic field. This only oc- 

 curs at pressures below 0.2 millimetre of mercury. 



Effect of Field on Fluids. Jager ( Vienna Acad- 

 emy Sitzungsberichte, 108, 1899), in experiments 

 on the behavior of fluids in the magnetic field, 

 could not observe the least change in the capil- 

 larity constant of a liquid in a powerful field. 

 Theory indicates, however, that when such liquid 

 is a solution in a nonmagnetic solvent a change 

 in vapor tension must occur, accompanied by a 

 calculable potential difference. An attempt to 

 confirm this experimentally was indecisive. 



Effect on Elasticity. Stevens and Dorsey (Phys- 

 ical Review, August, 1899), in experiments on the 

 effect of magnetism on the elasticity of rods, find 

 that the modulus of elasticity of wrought iron and 

 steel increases with magnetization. In the case of 

 steel little difference was observed for loads of 1 

 kilogramme and kilogramme, but in wrought 

 iron the smaller load gave the greater displacement 

 when equal magnetizing forces were used. 



Diamagnetism. Meyer (Annalen der Physik, 

 April), noting the fact that in some diamagnetic 

 compounds the molecular magnetism shows a 

 greater diamagnetic value than would correspond 

 to the sum of the atomic magnetisms, and that 

 this is so in every case where the combination is 

 accompanied by considerable expansion, has inves- 

 steel increases with magnetization. In the case of 

 contraction. Measurements made on copper salts 

 show that expansion emphasizes the diamagnetic 

 character of a substance, and contraction empha- 

 sizes its paramagnetic character. The magnetic 

 properties of the elements can therefore only be 



obtained from the elements themselves, or from 

 compounds whose formation entails no change of 

 volume. 



Instruments. Du Bois (Zeitschrift fiir Instru- 

 mentenkraft, April and May) describes a new form 

 of his magnetic balance, for which he claims an 

 accuracy five times that of the original type. The 

 most important improvement lies in a compensa- 

 tion coil wound outside the main exciting coil, 

 which neutralizes the stray field between the test 

 rod and the outer windings. 



Miscellany. Range of Observable Phenomena. 

 Stoney (Dublin Royal Society, 9, p. 79) classi- 

 fies the various measurable distances as stellar dis- 

 tances, planetary intervals, laboratory measures, 

 and molecular quantities. Each stands to the next 

 in the ratio of 10 10 to 1. Light, by its wonderful 

 speed, brings within our grasp the enormous dis- 

 tance of the first group, and also brings us into 

 touch with extremely minute intervals by the 

 smallness of its wave lengths. A further subdivi- 

 sion is, to us, meaningless, and hence the known 

 universe is comprised between the limits of ultra- 

 stellar remoteness and infra-molecular proximity. 

 Large as the range is, it might be infinitely larger 

 in both directions, and it resembles an absorption 

 band in a spectrum, representing the small portion 

 of the material universe accessible to human 

 faculties. 



PHYSIOLOGY. Respiration. In experi- 

 ments by Dr. H. Wendelstadt, of Bonn, on the 

 action of alcohol upon respiration, a small gas- 

 ometer was closely applied to the mouth, while the 

 subject was lying down, for ten minutes, and the 

 quantity of air breathed was read off every ten 

 seconds. The number of respirations was also 

 counted in some of the later experiments. The 

 temperature of the room w r as kept as nearly as 

 possible at 65 F., and the experiments were con- 

 ducted partly in the morning, when no fatigue 

 had been undergone, and partly on subjects who 

 were more or less exhausted after muscular or 

 mental effort. Wine or pure alcohol mixed with 

 sweetened lemonade was administered in moderate 

 doses. In most cases much drowsiness or even 

 heavy sleep was induced. The general results ob- 

 tained in men who were not fatigued were that 

 in one experiment there was no alteration in the 

 volume of air respired, in 9 experiments there was 

 a diminution, and in 54 cases there was an incroa-e 

 after the use of alcohol, but with much individual 

 variation. In 29 cases in which pure alcohol was 

 ingested, 7 showed diminution of respiratory activ- 

 ity, but when the alcohol was taken in the form 

 of wine only 2 showed such diminution, while the 

 amount of increase in every case where it occur MM! 

 was greater. The difference, Dr. Wendelstadt 

 thinks, is attributable to the presence of H hereal 

 oils in the wine giving it its bouquet. It shoulil 

 be borne in mind that, although it has been found 

 that the administration of 100 cubic centimetre-. 

 of pure water does "rt augment the volume " 

 respired air in a given time the same quantity 

 of water with sugar and K.no iii'-e j-aii-cs. .n i 

 in some instances, a slight ii crease. In persons 

 who are exhausted by fatigue, the effects of alco- 

 hol in causing an increase in the volume of ai 

 breathed are much more marked. Since in febrile 

 and debilitated states of the body the condition 

 of the nervous system resembles that of a person 

 exhausted by fatigue, Dr. Wendelstadt's experi- 

 ments may be regarded as corroborating the con- 

 clusions arrived at by most clinical observers, that 

 in such conditions alcohol is the best stimulant 

 that can be given. 



Dr. Leonard Hill, having subjected cata and 

 to conditions of atmospheric pressure similar to 



